Allergy Flashcards
Anaphylaxis, type and etiology?
Type 1
IgE to mast cells
Degranulation
Vasodilation
Anaphylaxis, presentation
Low BP Fast or slow HR Hives, prurits angiodema headache, vomiting diarrhea, SOB, cough
Autoimmune hemolytic anemia, type and etiology?
Type 2, cytotoxic
IgG bind to RBCs, leading to premature destruction,
-1/2 cases idiopathic
Autoimmune hemolyic anemia, presentation?
Symptoms - non specific, may have general symptoms of anemia -fatigue etc.
- jaundice or splenomegaly
- reticulocytes in peripheral blood smear
Poststreptococcal glomerulonephritis, type and etiology?
Type 3, Immune complex mediated
- prior infection of beta hemolytic strep
- immune complexes form and get stuck in glomeruli
Contact Dermatitis, type?
Type 4, Delayed Hype reaction
PSGN background info?
History of pharyngitis summer
-or impetigo in winter
Contact dermatitis, etiology?
Phase 1- sensitization
Phase 2- Allergic response after preexposure.
May take months or years to see response
Contact dermatitis, symtoms?
Primary= intense pruritis
Pain with excoriation, risk of secondary infection
-transient erythema, vesiculation, swelling with bullae
Serum sickness, type and etiology?
Type 3, ICF
admin of nonhuman protein leads to AB response
- ICF deposits in small vessels/tissues = vasculitis and tissue injury
Ex. antitoxins and antivenims
Vasculitis, type and etiology?
Type 3, ICF
Immune complexes get stuck in vessel walls.
Three types of vasculitis?
Small- Henochschonlein purpurn
Medium - Kawasaki disease
Large vessel - Giant cell(temporal) arteritis
Symptoms of vasculitis?
Regardless of size, systemic inflammation:
- fever, night sweats
- fatigue, anorexia, weight loss
- arthralgias, arthritis
SMall= thick palpable purpura
Transplant rejection, type and etiology?
Type 4, delayed
Graft destruction caused by T cell-mediated to allograft histocompatibility antignes
Transplant rejection, symptoms
Broad: fevers, chills, malaise, arthralgias
Anaphylaxis vs. anaphylactoid?
Anaphylaxis = IgE dependent
Anaphylactoid = IgE independent
- no sensitization required
- can occur on first exposure
- not predicted by skin test
Urticaria
Hives
Swelling of upper dermis
rasied blebs (wheals) with circuscribed edges (red halo)
Itching (pruritis)
Angioedema -acquired
swelling of the deep dermis
characterized by pain or burning not pruritus
-typically affects the face
Angioedema - hereditary
deficiency of complement inhibitors
leads to recurrent potentially life threatening attacks facial, laryngeal and GI swelling
Urticaria and angiodema pathphys, and Treatment?
-Type 1 hypersensitivity, degranulation of mast cells
Histamine binds to H1 and H2, causing aterial dilation, venous constriction, increased capillary permeability
Treatment: ovar H1 antihistamine
Atopic diseases
- allergic rhinitis
- atopic dermatitis
- allergic asthma
- allergic gastroenteropathy
Food allergy vs. food intolerance?
allergy = specific immune response
-potentially life threatening
intolerance = associated with digestion
- not life threatening
Most common food allergies?
IgE associated:
- milk, eggs, peanut, soy, wheat, tree nuts, fish, shellfish
- asthma and urticaria not likely to be caused by food allergies
exanthematous/
morbilliform
Etiology: commonly penicillin family
S&S: “rash all over,” widespread symmetric, erythematous macules and papules on the trunk and extremities, pruritus, mild, fever
-First exposure rash after 7-10 days
Most common of all cutaneous drug eruptions (90%)
- Stop medication, resolves a few days to a week after the medication is stopped, can continue medication if not too severe and meds can’t be substituted, resolves without sequelae
- Treat: topical steriods and oral antihistamines
Fixed Drug Eruption Etiology
commonly: phenolphthalein tetracyclines metronidazole sulfonamides NSAIDS salicylates
Fixed drug eruption S&S
erythematous patch with central bulla, same location with re-exposure
- often affects acral areas
- 30 min to 8hrs from exposure
- healed lesions dark brown or purple
Fixed drug eruption Diag work up and management
stop meds, should resolve days to weeks
- non eroded lesions can use topical steriod
- eroded lesions can use antimicrobial ointment
- if widespread and generalized refer to derm
Drug related eosinophilia w/ systemic symptoms
DIHS or DRESS
Etiology
Etiology: Sulfa drugs penicilin minocycline, metronidzole isoniazid phenytoin diclocfenac meloxicam abacavir
Drug related eosinophilia w/ systemic S&S and PE findings
DIHS or DRESS
Fever, malaise, start typically 3rd wk, (1-12wks)
Patient is sick looking with rash!
Facial edema, diffuse erythematous macules and plaques, Trunk and extremities.
Organ involvement
CBC, LFT, BUN, creatinine
Elevated WBC, AST, Atypical lymphocytes
consult derm and stop meds
if not severe can use topical steroids and systemic antihistamines
Steven-Johnson syndrome
Toxic Epidermal necrolysis etiology
Sulfa antibotics, sulfasalazine Allopurinol Tetracyclines, Thiacetrazone Anticonvulsants (carbamezapine, phenbarbital, phentoin, lamotrigine NSAIDS, Nevirapine
Steven-Johnson syndrome
Toxic Epidermal necrolysis S&S
Painful sloughing rash. Flaccid blisters that spread with pressure. 8 weeks after exposure.
- Fever, headaches, malaise before lesions 1-3 days preceding lesions
-Initial lesions irregular red to purpuric macules.
Could have mucous membrane involvement
- Erythematous erosions, open skin, begin as flaccid blisters
- if 30% BSA = toxic epidermal necrolysis
- punch tissue biopsy, if 25-30% BSA = burn unit
- discontinue all non life sustaining meds. If skin is dusky gray , necrosis is likely
Manifestations of IgE: eyes
Swelling of conjunctiva
Manifestations of IgE: skin
Uriticaria (hives)
Pruritis (itching)
flushing
Manifestations of IgE: Respiratory tract
SOB wheezes/stridor hoarseness pain with swallowing cough
Manifestations of IgE: Heart
fast or slow HR
Low BP
Manifestations of IgE: GI tract
crampy/ abdominal pain diarrhea vomiting rhinorrhea swelling of lips and tongue and throat pelvic pain loss of bladder control
Manifestations of IgE: Neuro
lightheadedness loss of consciousness confusion headache anxiety
